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PubMed2003

Growth dynamics of Salmonella enterica strains on alfalfa sprouts and in waste seed irrigation water.

Alfalfa sprouts and other seed sprouts have been implicated in numerous outbreaks of salmonellosis. The source of these epidemics appears to have been low-level contamination of seeds by Salmonella bacteria that developed into clinically significant populations during the seed germination process. To test the possibility that Salmonella enterica strains carry host range determinants that allow them to grow on alfalfa, strains isolated from alfalfa or other sources were surveyed for their ability to grow on germinating alfalfa seeds. An S. enterica serovar Cubana strain originally isolated from contaminated alfalfa sprouts multiplied most rapidly during the initial 24 h of the seed germination process. Germinating alfalfa seeds supported the multiplication of S. enterica cells prior to the emergence of the root radicle at 72 h. Thereafter, much lower rates of multiplication were apparent. The ability of S. enterica to grow on germinating alfalfa seeds was independent of the serovar, isolation source, or virulence of the strain. Isolates obtained from alfalfa attained population levels similar to those observed for strains isolated from contaminated meat products or stools. Each of the strains could be detected in the waste irrigation water, with populations being strongly correlated with those detected on the germinating alfalfa seeds. The S. enterica strains were capable of utilizing the waste irrigation water as a sole carbon and nitrogen source. S. enterica strains thus appear to grow saprophytically on soluble organics released from seeds during early phases of germination. The ability to detect S. enterica in the waste irrigation water early in the germination process indicates that this method may be used as a simple way to monitor the contamination of sprouts during commercial operations.

Animals↗
PubMed1971

Influence of fungicides and irrigation practice on aflatoxin in peantus before digging.

Peanuts grown under dryland conditions where drought stress occurred accumulated more aflatoxin before digging than peanuts grown under irrigation. Kernels became more susceptible to Aspergillus flavus and A. parasiticus invasion when the soil moisture in the pod zone approached levels at which moisture moved from the pod into the soil and the kernel moisture dropped below 31%. Isolation frequencies of these aspergilli from fresh-dug kernels were lowest in 1968 (maximum of 3%). In 1967 and 1969, maximum percentages of 100 and 74, respectively, were noted. Kernel infestation was correlated with degree of aflatoxin contamination. Dryland fresh-dug kernels contained a maximum of 35,800 parts per billion aflatoxin while a maximum of 50 parts per billion was detected in kernels from irrigated plots. In 1969 A. flavus infestation was as high as 59% in peanuts from irrigated plots; however, no aflatoxin was detected. Absence of aflatoxin in these samples is attributed to the higher kernel moisture content which reduced the aflatoxin-producing potential of A. flavus. Statistical analysis of the data revealed no significant differences in degree of fungal infestation, production levels, and grade factors between any fungicide treatments.

Acetone↗
PubMed2004

Fate of Escherichia coli O157:H7 in irrigation water on soils and plants as validated by culture method and real-time PCR.

One of the most common vehicles by which Escherichia coli O157:H7 may be introduced into crops is contaminated irrigation water. Water contamination is becoming more common in rural areas of the United States as a result of large animal operations, and up to 40% of tested drinking-water wells are contaminated with E. coli. In this study, 2 contrasting soil samples were inoculated with E. coli O157:H7 expressing green fluorescent protein through irrigation water. Real-time PCR and culture methods were used to quantify the fate of this pathogen in phyllosphere (leaf surface), rhizosphere (volume of soil tightly held by plant roots), and non-rhizosphere soils. A real-time PCR assay was designed with the eae gene of E. coli O157:H7. The probe was incorporated into real-time PCR containing DNA extracted from the phyllosphere, rhizosphere, and non-rhizosphere soils. The detection limit for E. coli O157:H7 quantification by real-time PCR was 1.2 x 10(3) in the rhizosphere, phyllosphere, and non-rhizosphere samples. E. coli O157:H7 concentrations were higher in the rhizosphere than in the non-rhizosphere soils and leaf surfaces, and persisted longer in clay soil. The persistence of E. coli O157:H7 in phyllosphere, rhizosphere, and non-rhizosphere soils over 45 days may play a significant part in the recontamination cycle of produce in the environment. Therefore, the rapidity of the real-time PCR assay may be a useful tool for quantification and monitoring of E. coli O157:H7 in irrigation water and on contaminated fresh produce.

Adhesins, Bacterial↗
PubMed1999

Risk screening for exposure to groundwater pollution in a wastewater irrigation district of the Mexico City region.

Untreated wastewater from the Mexico City basin has been used for decades to irrigate cropland in the Mezquital Valley, State of Hidalgo, Mexico. Excess irrigation water recharges the near-surface aquifer that is used as a domestic water supply source. We assessed the groundwater quality of three key groundwater sources of domestic water by analyzing for 24 trace metals, 67 target base/neutral/acid (BNA) organic compounds, nontarget BNA organics, 23 chlorinated pesticides, 20 polychlorinated biphenyls, and nitrate, as well as microbiological contaminants--coliforms, Vibrio cholerae, and Salmonella. Study participants answered a questionnaire that estimated ingestion and dermal exposure to groundwater; 10% of the sample reported frequent diarrhea and 9% reported persistent skin irritations. Detection of V. cholerae non-01 in surface waters at all sites suggested a potential risk (surrogate indicator present) of diarrheal disease for canal and river bathers by accidental ingestion, as well as potential Vibrio contamination of near-surface groundwater and potential cholera risk, magnified by lapses in disinfection. High total coliform levels in surface water and lower levels in groundwater at all sites indicated fecal contamination and a potential risk of gastrointestinal disease in populations exposed to inadequately disinfected groundwater. Using chemical criteria, no significant risk from ingestion or dermal contact was identified at the method detection limits at any site, except from nitrate exposure: infants and young children are at risk from methemoglobinemia at all sites. Results suggest that pathogen risk interventions are a priority, whereas nitrate risk needs further characterization to determine if formal treatment is needed. The risks exist inside and outside the irrigation district. The method was highly cost-effective.

Humans↗
PubMedDate not supplied

Anaerobically treated wastewater in agricultural irrigation as an alternative for posttreatment in water-demanding zones.

Agroindustries usually produce high amounts of wastewaters and are frequently located close to agricultural activities. Agricultural use of treated wastewaters therefore represents a unique opportunity to solve the problem of water supply for irrigation and disposal of treated water at the same time. This article is the result of collaborative work with the biggest Chilean pisco- (a distillated drink prepared from Muscatel wine) producing company at present. Experiments were conducted to establish anaerobic treatability of wastewaters and also irrigation properties of treated water. With the purpose of confirming laboratory results, a full-scale anaerobic plant was built, and treated water is being used to irrigate 3000 eucalypti. The results showed, at both laboratory and full scale, that anaerobic treatment is suitable for the treatment of pisco wastewater, and that nutrient content of treated water can be beneficial for plant growth, reducing the need for fertilizers.

Agriculture↗
PubMed2004

Bipolar irrigated radiofrequency ablation of the posterior-inferior left atrium and coronary sinus is feasible and safe.

BACKGROUND: Success of surgical therapy for atrial fibrillation (AF) mainly depends on creating a complete set of transmural atrial lesions. The established Cox procedures may be simplified by dropping lesions, but not without the risk of impaired results. We aimed to create a complete set of lesions using bipolar irrigated radiofrequency including ablation of the posterior-inferior left atrium (LA) and coronary sinus. Feasibility and safety were investigated. METHODS: Six patients (mean age 63 +/- 14 years) with continuous AF (duration 15 +/- 8 months) underwent elective heart surgery for isolated mitral valve procedures (n = 4), in combination with myocardial revascularization (n = 1) or isolated bypass surgery (n = 1). Ablation of AF was performed using bipolar irrigated radiofrequency to create a modified Cox minimaze pattern. RESULTS: No major intraoperative or postoperative complication occurred. Two patients left the operating room in sinus rhythm and 4 in junctional rhythm with atrioventricular pacing. AF ablation required 20 +/- 5 minutes. CONCLUSIONS: Bipolar irrigated radiofrequency ablation including ablation of the posterior-inferior LA and coronary sinus is feasible and can be performed safety. Long-term studies in large patient cohorts are necessary to show efficiency of this method.

Absorptiometry, Photon↗
PubMed1988

Ultrastructural examination of human periodontal pockets following the use of an oral irrigation device in vivo.

To date, there are no ultrastructural studies that have examined untreated chronic periodontal pockets immediately following dental debridement with an oral irrigation device. This study used both scanning electron microscopic and transmission electron microscopic methodology to examine previously untreated human periodontal pockets after their exposure to a pulsating oral irrigation with saline solution. A comparison of 16 untreated controls with 16 test specimens revealed qualitative differences in microbial morphotypes at various pocket depths. Control specimens at all pocket depths examined (0-6 mm), exhibited a mixed microbial flora consisting of cocci, short rods, and filamentous organisms. Specifically at 3- to 4-mm and 5- to 6-mm levels in control specimens, spirochetes, fusiforms, and branching organisms were obvious. In contrast, test specimens exhibited a few cocci and short rods at 0- to 2-mm and 3- to 4-mm levels and a mixed flora at the 5- to 6-mm level. There was no observable difference between control and test specimens concerning epithelial topography, cavitations, microulcerations, spatial relationships, and individual cell appearance. Both control and test specimens exhibited a mild spirochete invasion of the epithelial strata. Collectively these observations suggest that pulsating oral irrigation effects a qualitative change on subgingival plaque and is not injurious to the soft tissues.

Adult↗
PubMed1991

Effects of wastewater irrigation of pastures on the health of farm animals and humans.

Wastewater recycling and reuse through agricultural irrigation can provide an economical means of preventing pollution of surface water sources, while conserving water resources and valuable nutrients for increased crop production and grazing pastures. With proper methods of wastewater treatment, health risks to farmers and farm animals as well as to the public who consume agricultural produce can be prevented. The possibility of transmission of the beef tapeworm Taenia saginata, Salmonella sp. and Mycobacteria sp. to farm animals grazing on wastewater-irrigated pasture is evaluated. While such transmission is possible when raw, untreated wastewater is used for irrigation, the risk is greatly reduced and essentially eliminated with effluent treated to meet the new World Health Organisation (WHO) recommended microbial guidelines for effluent. These guidelines call for one or less helminth eggs per litre and a mean of 1,000 faecal coliform bacteria per 100 ml. In warm climates and where land is available, one of the most economical methods of achieving this standard is the use of multi-cell stabilisation ponds designed for a 25-day detention period. In colder climates and where land is a limiting factor of wastewater treatment, conventional secondary biological treatment followed by disinfection can also be applied to meet this standard.

Agriculture↗
PubMed1989

Gastrointestinal effects of water reuse for public park irrigation.

To investigate the gastrointestinal effects of employing recycled water as an irrigation source for urban public parks, we studied subjects active in parks irrigated with potable water, nonpotable water of wastewater origin, and nonpotable water of runoff origin. Wet grass conditions during activity and elevated densities of common indicator bacteria, but not exposure to nonpotable irrigation water per se, were found associated with an increased rate of gastrointestinal illness.

Adolescent↗
PubMedDate not supplied

Nitrate and chloride loading to groundwater from an irrigated north-central U.S. sand-plain vegatable field.

Groundwater pollution and associated effects on drinking water have increased with the expansion of irrigated agriculture in north-central U.S. sand plains. Controlling this pollution requires an ability to measure and predict pollutant loading by specific agricultural systems. We measured NO3 and Cl loading to groundwater beneath a Wisconsin central sand plain irrigated vegetable field using both a budget method and a new monitoring-based method. By relying on frequent monitoring of shallow groundwater, the new method overcomes some limitations of other methods. Monitoring-based and budget methods agreed well, and indicated that loading to groundwater was 165 kg ha(-1) NO3-N and 111 kg ha(-1) Cl for sweet corn (Zea mays L.) in 1992, and 228 kg ha(-1) NO3-N and 366 kg ha(-1) Cl for potato (Solanum tuberosum L.) in 1993. Nitrate N loading was 56 to 60% of available N, or 66 to 70% of fertilizer N. Sweet corn NO3 loading was about typical for this region, but potato NO3 loading was probably 50% greater than typical because heavy rains provoked extra fertilizer application. Our results imply that typical NO3-N loading would be 119 kg ha(-1) for sweet corn and 203 kg ha(-1) for potato, even with strict adherence to University Extension fertilizer recommendations. To keep average groundwater NO3-N within the 10 mg L(-1) U.S. drinking water standard, each irrigated vegetable field would need to be offset by five to eight times as much land supplying NO3-free groundwater recharge.

Agriculture↗
PubMedDate not supplied

Phytoremediation of aged petroleum sludge: effect of irrigation techniques and scheduling.

The use of higher plants to accelerate the remediation of petroleum contaminants in soil is limited by, among other factors, rooting depth and the delivery of nutrients to the microsites at which remediation occurs. The objective of this study was to test methods of enhancing root growth and remediation in the subsurface of a contaminated petroleum sludge. The phytoremediation of highly contaminated petroleum sludge (total petroleum hydrocarbons >35 g kg(-1) was tested in the greenhouse as a function of the frequency and the depth of irrigation and fertilization. Water and dissolved plant nutrients were added to the soil surface or at a depth of 30 cm, either daily or weekly. Equivalent quantities of water and nutrients were added in all cases. Daily irrigation at a depth of 30 cm invoked greater root growth and enhanced contaminant degradation relative to all other treatments. In the absence of plants, residual concentrations of petroleum hydrocarbons after 7 mo were higher than with plants. The presence of plant roots clearly improved the physical structure of the soil and increased microbial populations. Thus, the plant roots in conjunction with daily additions of soluble N and P appeared to enhance oxygen transport to greater depths in the soil, stimulate petroleum-degrading microorganisms, and provide microbial access to soil micropores. Subsurface irrigation with frequent, small amounts of water and nutrients could significantly accelerate phytoremediation of field soils contaminated with petroleum hydrocarbons.

Agriculture↗
PubMedDate not supplied

Irrigation of broccoli and canola with boron- and selenium-laden effluent.

Selenium (Se), boron (B), and salinity contamination of agricultural drainage water is potentially hazardous for water reuse strategies in central California. To demonstrate the feasibility of using plants to extract Se from drainage water, Se accumulation was determined in canola (Brassica napus L.) and broccoli (Brassica oleracea L.) irrigated with drainage effluent in the San Joaquin Valley, California. In the 2-yr field study, both crops were irrigated with a typical drainage water containing Se (150 microg L(-1)), B (5 mg L(-1)), and a sulfate dominated salinity (EC of 7 dS m(-1)). Total dry matter yields were at least 11 Mg ha(-1) for both canola and broccoli, and plant tissue Se concentrations did not exceed 7 mg kg(-1) DM for either crop. Based on the amount of soluble Se applied to crops with drainage water and the estimated amount of soluble Se remaining in soil to a depth of 90 cm at harvest, both canola and broccoli accumulated at least 40% of the estimated soluble Se lost from the soil for both years. Applied Se not accounted for in plant tissue or as soluble Se in the soil was presumably lost by biological volatilization. This study suggests that irrigating two high value crops such as canola and broccoli with Se-laden effluent helps manage Se-laden effluent requiring treatment, and also produces economically viable Se-enriched crops. Future research should focus on managing residual salt and B in the soil for sustaining long time water reuse strategies.

Agriculture↗
PubMedDate not supplied

Irrigated mountain meadow fertilizer application timing effects on overland flow water quality.

Nonpoint-source pollution from agricultural activities is currently the leading cause of degradation of waterways in the United States. Applying best management practices to flood-irrigated mountain meadows may improve agricultural runoff and return flow water quality. Prior research has focused on fertilizer use for increased hay yields, while few studies have investigated the environmental implications of this practice. We examined the effects of fertilizer application timing on overland flow water quality from an irrigated mountain meadow near Gunnison, Colorado. Application of 40 kg phosphorus (P) and 19 kg nitrogen (N) ha(-1) using monoammonium phosphate (11-52-0, N-P-K) fertilizer to plots in the fall significantly reduced concentrations of reactive P and ammonium N in irrigation overland flow compared with early or late spring fertilization. Reactive P loading was 9 to almost 16 times greater when fertilizer was applied in the early or late spring, respectively, compared with in the fall. Ammonium N followed a similar trend with early spring loading more than 18 times greater and late spring loading more than 34 times greater than loads from fall-fertilized plots. Losses of 45% of the applied P and more than 17% of the N were measured in runoff when fertilizer was applied in the late spring. These results, coupled with those from previous studies, suggest that mountain meadow hay producers should apply fertilizer in the fall, especially P-based fertilizers, to improve hay yields, avoid economic losses from loss of applied fertilizers, and reduce the potential for impacts to water quality.

Agriculture↗
PubMed2006

Microbiological quality of reclaimed water used for golf courses' irrigation.

Microbial quality of reclaimed water used for irrigation in two golf courses located in the southern Iberian Peninsula (Spain and Portugal) was evaluated. Bacterial indicators for faecal pollution (total and faecal coliforms, Escherichia coli and enterococci) were tested by membrane filtration using appropriate selective media. In addition, somatic E. coli bacteriophages, enteric viruses (entero-, hepatitis A and rota-) and Legionella pneumophila were also analysed. The results obtained showed that all wastewater treatment processes reduced adequately the number of indicator microorganisms although a significant correlation between pathogenic and indicator microorganisms tested was not found. L. pneumophila was detected by PCR but not confirmed by culture. Survival experiments of pathogenic microorganisms in aerosols and irrigated turf are conducted to determine the health hazards for the golf practice and to propose a microbial standard for wastewater used for irrigation of golf courses.

Base Sequence↗
PubMed2006

Survival of total coliforms in lawn irrigated with secondary wastewater and chlorinated effluent in the Mediterranean region.

Pregrown, two-month-old lawn was layered in 12 large square pots with an area of 0.25 m2 each, filled with a mixture of topsoil, peat, and sand. In late July, in the heart of the Mediterranean summer, the pots were divided into two groups, with six pots per group. On four different occasions, the pots in each group were sprinkled (surface irrigation) with 2 L of either secondary-treated wastewater (STW, group A) or chlorinated effluent (CHE, group B). Wastewater application always took place at 0700 hours. Samples of the surface soil and grass from each pot were collected at the following times: before irrigation, immediately after irrigation, two hours later (0900 hours), and four hours later (1100 hours). In the samples collected, the number of total coliforms per gram was measured using standard microbiological analyses. Temperature and sunlight intensity were also monitored. There was an increase in the coliforms population in soil and grass samples of both groups immediately after the wastewater application. In group A, the mean number of coliforms recorded in the soil samples reached mean values higher than 5000 cfu/g compared to 312 cfu/g recorded before application. The increase in group B was smaller but still significant. Two hours later, the number of coliforms was reduced substantially in all samples (e.g., group A, soil samples 477 cfu/g). Coliform inactivation is thought to result from the effect of temperature and mainly sunlight. However, four hours after application (1100 hours), there was a noticeable increase in the coliform number again, in all sample categories of both groups. Coliform reactivation could be a result of shadowing effect resulting from the thick foliage of the grass, where the microorganisms were protected by the sunlight radiation and regrowth in a friendly environment (especially of the soil) where moisture and nutrients were present. This, in addition to the fact that coliforms seemed to retain a sizable population between applications, results in three conclusions: (1) coliforms can survive in grass and soil for a substantial period of time, recovering from the destructive effect of chlorination, (2) use of STW, even during the Mediterranean summer, could result in a substantial "contamination" of lawns, without any proof that sun and temperature can reduce the coliform number, and (3) intense sunlight (up to 68 000 lux) was far more effective in coliform suppression than elevated temperature (up to 38 degrees C).

Agriculture↗
PubMed1989

Diet composition and daily gain of growing cattle grazing dryland and irrigated cornstalks at several stocking rates.

Diet composition and the relationships between daily gain of calves grazing cornstalks and certain characteristics of the available residue and diets selected by esophageally fistulated cattle were studied in two trials during November and December of 1984 (Trial 1) and of 1986 (Trial 2). Eight adult steers and four esophageally fistulated calves were used in Trials 1 and 2, respectively, to collect extrusa samples from dryland and irrigated fields grazed at several stocking rates. Steers grazing irrigated cornstalks selected a diet with more (P less than .05) starch and less (P less than .05) CP than those grazing dryland fields. As grazing continued, extrusa starch content decreased (P less than .05). In vitro DM disappearance (IVDMD) of both diet and the roughage fraction of the diet decreased (P less than .05) with days of grazing; this decrease was greater (P less than .05) at higher stocking rates. Calves grazing dryland fields gained faster (P less than .05) than calves grazing irrigated fields. With a low level of protein supplementation (213 g CP/d, Trial 1), daily gain was positively correlated with CP of both diet (extrusa) or available leaf plus husk but not with grain available per animal or with extrusa IVDMD, suggesting that protein was first limiting. With a higher level of protein supplementation (458 g CP/d, Trial 2), daily gain was correlated positively with residue available per animal and IVDMD of extrusa at the end of the grazing season. The energy value of feed consumed by cattle grazing cornstalks decreases with time, and complex interactions between protein needs and energy intake may occur.

Animal Feed↗
PubMed1995

Simulated intraperitoneal absorption of irrigating fluid.

BACKGROUND: Intraperitoneal absorption of electrolyte-free irrigating fluid may occur secondary to uterine perforation during endometrial resection, but the clinical course of this complication is known from only a few case reports. METHODS: We studied symptoms, biochemical changes and the kinetics of solute equilibration over the peritoneal membrane in 10 healthy awake women who were subjected to an experimental absorption situation by receiving an intraperitoneal infusion of 25 ml/kg of a solution containing glycine 1.5% and ethanol 1% over 20 min. We also compared the use of breath ethanol and serum sodium samples to indicate the presence of irrigating fluid in the peritoneal cavity. RESULTS: All infusions caused lower abdominal pain. The solute gradients between the peritoneal pool and plasma were reduced according to mono-exponential functions with a half-time of 33 +/- 5 min for ethanol, 92 +/- 9 min for sodium, 103 +/- 9 min for potassium, and 124 +/- 10 min for amino acids (mean +/- s.e.mean). Twenty minutes after infusion, the breath ethanol level reached a plateau which could be used to predict the infused volume within +/- 15% of the true value. In contrast, the serum sodium concentration decreased slowly and was only 3.0 +/- 0.7 mmol/l below baseline at 2 hours after infusion. CONCLUSIONS: The calculated rates of transperitoneal solute equilibration can be used to assess the need for substitution of electrolytes in patients who absorb irrigating fluid into the peritoneal cavity. Measurement of ethanol in the expired breath is more useful than serum sodium to indicate the existence of such a pool.

Absorption↗
PubMed2002

Prevalence of Escherichia coli associated with a cabbage crop inadvertently irrigated with partially treated sewage wastewater.

Preharvest contamination of field crops may have many sources, including feces, soil, and irrigation water. In March 2000, a sewage spill released unchlorinated tertiary-treated effluent into a creek used to irrigate commercial produce. A field of young cabbage transplants was irrigated with creek water as the contaminated water flowed past this land. Cabbage samples were taken from plots within this field, and Escherichia coli was isolated from the roots of these plants but not from the edible portion of the cabbage. No E. coli was isolated from water samples or from control samples taken from a nearby cabbage field watered with chlorinated municipal water. The cabbage field under study had not been fertilized with manure for at least 2 years prior to the contamination incident. Six different E. coli serotypes were identified, although none of them proved to be pathogenic. These serotypes were separated into five groups by a RiboPrinter; the resulting groups correlated well with the serotypes and the locations in the field from which these strains were isolated. We previously found that certain nonpathogenic E. coli strains displayed lower levels of adherence to lettuce seedling roots in a hydroponic adherence assay. The E. coli field strains displayed variable patterns of adherence to lettuce seedlings: strain MW421 showed significantly lower root and shoot adherence levels than did the other field strains, while strains MW423 and MW425 showed significantly higher root and shoot adherence levels. These data suggest that water quality is of paramount importance for the food safety of growing crops.

Bacterial Adhesion↗